CN102553604A - Method for implementing Cu<2+> doping modification on BiVO4 photocatalyst by using microwave hydrothermal method - Google Patents

Abstract

The invention discloses a method for implementing Cu<2+> doping modification on a BiVO4 photocatalyst by using a microwave hydrothermal method. The method comprises the following steps of: dissolving Bi(NO3)3.5H2O and Cu(NO3)2.3H2O into HNO3 to form a mother salt solution B; dissolving NH4VO3 into a NaOH solution to form a mother salt solution A; and mixing the mother salt solutions A and B, stirring uniformly to form a precursor solution, adding the precursor solution into a microwave hydrothermal reaction kettle, performing microwave hydrothermal reaction, cooling after the reaction is finished, taking yellow sediment in the reaction kettle out, washing and drying. The Cu<2+>-doped BiVO4 powder is quickly synthesized by adopting the microwave hydrothermal synthesis technology, and the photocatalytic efficiency of pure phase BiVO4 powder is improved. The powder obtained by using the method is uniform in granularity distribution, the process is simple and easily controlled, the preparation period is short, energy is saved, and the method has a very wide application prospect.

Description

Microwave-hydrothermal method is to BiVO 4Photochemical catalyst carries out Cu 2+The method of doping vario-property

Technical field

The invention belongs to field of functional materials, relate to microwave-hydrothermal method BiVO ₄Photochemical catalyst carries out Cu ²⁺The method of doping vario-property.

Background technology

Monocline crystalline phase pucherite energy gap is 2.3-2.4eV, and its valence band oxidizing potential is positioned near the 2.4eV, at present mBiVO ₄Be applied to the research of degradation of contaminant, photodissociation aquatic products oxygen and Optical Electro-Chemistry decomposition water.Yet mBiVO ₄The conduction band limit be positioned at 0v (vs.NHE), the energy shortage that causes its light induced electron is with reduction H ⁺, and its light induced electron also is not easy to be caught by airborne oxygen, therefore can cause light induced electron to accumulate at catalyst surface, thus increase the recombination probability in electronics and hole, cause mBiVO ₄The organic efficient of degraded is relatively poor under visible light.And productive rate in the preparation is very low, and this has also improved its preparation cost to a certain extent, has limited it and has further promoted practical application.

In order further to improve the photocatalysis efficiency of pucherite, the present invention adopts Cu ²⁺It is mixed, with Cu ²⁺Introduce BiVO ₄Lattice in, between valence band and conduction band, form new energy level, help photic electronics and move to the outside, prevent the simple composite of electron hole, can improve light-catalyzed reaction efficient and selectivity.At present to BiVO ₄Mostly the method for carrying out doping vario-property is infusion process, is promptly preparing pure phase BiVO in conventional solid state reaction method, chemical coprecipitation, sol-gel process and hydro-thermal method etc. ₄After, selecting the proper metal source to adopt the method for dipping that it is mixed, this method flow is many, complex process.Microwave-hydrothermal method as mode of heating, prepares a kind of new method of nano-powder or powder with microwave in conjunction with traditional hydro-thermal method.As the method for the nano particle of a kind of quick preparation narrow diameter distribution, form homogeneous, microwave-hydrothermal method has the incomparable superiority of some other method.

Summary of the invention

The object of the present invention is to provide a kind of microwave-hydrothermal method to BiVO ₄Photochemical catalyst carries out Cu ²⁺The method of doping vario-property, this short in method reaction time, and technological process is simple, even particle size distribution and can well improve pure phase BiVO ₄Photocatalysis performance.

A kind of microwave-hydrothermal method is to BiVO ₄Photochemical catalyst carries out Cu ²⁺The method of doping vario-property may further comprise the steps:

Step 1: with NH ₄VO ₃Being dissolved in 20mL concentration is in the NaOH solution of 1～4mol/L, on magnetic stirring apparatus, stirs 10～20min, is mixed with female salting liquid A;

Step 2: with Cu (NO ₃) ₂3H ₂O and Bi (NO ₃) ₃5H ₂O is dissolved in the HNO that 20mL concentration is 2～6mol/L ₃In the solution, (n wherein _Cu+ n _Bi): n _V=1: 1, n _Cu: n _Bi=1%～15%, on magnetic stirring apparatus, stir 10～20min, be mixed with female salting liquid B;

Step 3: female salting liquid B that female salting liquid A that step 1 is obtained and step 2 obtain mixes, and on magnetic stirring apparatus, stirs 10～30min, is mixed with precursor solution;

Step 4: precursor solution is added in the microwave hydrothermal reaction kettle, and packing ratio is 40～60%, then agitated reactor is placed microwave auxiliary water thermal synthesis appearance, and setting reaction temperature is 180～220 ℃, and temperature retention time is 60～120min;

Step 5: after question response was accomplished, the yellow mercury oxide in the agitated reactor was taken out in cooling, spends deionised water to neutrality, uses absolute ethanol washing again, at 80 ℃ of following freeze-day with constant temperature, obtains powder at last.

Compared with prior art, the inventive method has the following advantages at least: the present invention is to BiVO ₄Photochemical catalyst carries out Cu ²⁺Doping vario-property, the photochemical catalyst powder after the modification are the ball structure that granule is agglomerated into, and simultaneously, under UV-irradiation, the catalytic effect of this powder can be up to 95%.

Description of drawings

Fig. 1 is the different Cu of the present invention ²⁺The XRD spectra of the powder for preparing under the doping;

Fig. 2 is Cu of the present invention ²⁺The EDS spectrogram of powder when doping is 2% (according to mol ratio);

Fig. 3 is Cu of the present invention ²⁺The FE-SEM of powder figure when doping is 2% (according to mol ratio);

Fig. 4 is the different Cu of the present invention ²⁺Degradation rate-time plot of the degraded rhodamine B of the powder for preparing under the doping.

The specific embodiment

Step 1: with NH ₄VO ₃Being dissolved in 20mL concentration is in the NaOH solution of 1～4mol/L, on magnetic stirring apparatus, stirs 10～20min, is mixed with female salting liquid A;

Step 2: with Cu (NO ₃) ₂3H ₂O and Bi (NO ₃) ₃5H ₂O is dissolved in the HNO that 20mL concentration is 2～6mol/L ₃In the solution, (n wherein _Cu+ n _Bi): n _V=1: 1, n _Cu: n _Bi=1%～15%, on magnetic stirring apparatus, stir 10～20min, be mixed with female salting liquid B;

Step 3: female salting liquid B that female salting liquid A that step 1 is obtained and step 2 obtain mixes, and on magnetic stirring apparatus, stirs 10～30min, is mixed with precursor solution;

Step 4: precursor solution is added in the microwave hydrothermal reaction kettle, and packing ratio is 40～60%, then agitated reactor is placed microwave auxiliary water thermal synthesis appearance, and setting reaction temperature is 180～220 ℃, and temperature retention time is 60～120min;

Step 5: after question response was accomplished, the yellow mercury oxide in the agitated reactor was taken out in cooling, spends deionised water to neutrality, uses absolute ethanol washing again, at 80 ℃ of following freeze-day with constant temperature, obtains powder at last.

In above-mentioned preparation method, the consumption of each reactant, proportionate relationship, and packing ratio, reaction temperature and temperature retention time that the microwave hydrothermal meal is answered are specifically referring to following subordinate list 1

Table 1

Fig. 1 is different Cu ²⁺The Cu/BiVO for preparing under the doping ₄XRD figure spectrum highest peak occurs during in 2 θ=28.850 °, conforms to the data JCPDS NO.14-0688 of standard P DF card, and be pure monocline phase pucherite.Fig. 2 is Cu ²⁺Doping is the EDS spectrogram of 2% (according to molar percentage) powder, can find out the characteristic peak that removes Bi, V and O, also has the characteristic peak of Cu, and this explanation Cu has appeared at BiVO ₄Crystal in.Fig. 3 is Cu of the present invention ²⁺The FE-SEM picture of powder when doping is 2% (according to molar percentage) can find out that prepared powder is the ball structure that granule is agglomerated into.Fig. 4 is different Cu under the ultraviolet light ²⁺The sample of doping is to the curve of rhodamine B degradation rate in time.By finding out among the figure that after ultraviolet light 4.5h irradiation doping is 2% Cu/BiVO ₄The catalyst effect is best, can reach 95%, and the catalytic effect under its doping is followed successively by the Cu/BiVO that doping is 2at.%＞1.5at.%＞1at.%＞0at.% from high to low ₄This explains Cu ²⁺Doping can improve BiVO ₄The photocatalysis effect.

The above is merely one embodiment of the present invention; It or not whole or unique embodiment; The conversion of any equivalence that those of ordinary skills take technical scheme of the present invention through reading specification of the present invention is claim of the present invention and contains.

Claims (1)

1. a microwave-hydrothermal method is to BiVO ₄Photochemical catalyst carries out Cu ²⁺The method of doping vario-property is characterized in that: may further comprise the steps:

Step 1: with NH ₄VO ₃Being dissolved in 20mL concentration is in the NaOH solution of 1～4mol/L, on magnetic stirring apparatus, stirs 10～20min, is mixed with female salting liquid A;

Step 2: with Cu (NO ₃) ₂3H ₂O and Bi (NO ₃) ₃5H ₂O is dissolved in the HNO that 20mL concentration is 2～6mol/L ₃In the solution, (n wherein _Cu+ n _Bi): n _V=1: 1, n _Cu: n _Bi=1%～15%, on magnetic stirring apparatus, stir 10～20min, be mixed with female salting liquid B;

Step 3: female salting liquid B that female salting liquid A that step 1 is obtained and step 2 obtain mixes, and on magnetic stirring apparatus, stirs 10～30min, is mixed with precursor solution;

Step 4: precursor solution is added in the microwave hydrothermal reaction kettle, and packing ratio is 40～60%, then agitated reactor is placed microwave auxiliary water thermal synthesis appearance, and setting reaction temperature is 180～220 ℃, and temperature retention time is 60～120min;

Step 5: after question response was accomplished, the yellow mercury oxide in the agitated reactor was taken out in cooling, spends deionised water to neutrality, uses absolute ethanol washing again, at 80 ℃ of following freeze-day with constant temperature, obtains powder at last.

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